Trend Discussion for Key Sources

The following charts give an overview and assistance for explainig dominant emission trends of selected pollutants.

Annual fluctuations of all fuel types in source catagory 1.A.4.b.i depend on heat demand subject to winter temperatures. Between 1990 and 2002 the fuel use changed considerably from coal & lignite to natural gas. The consumption of light heating oil decreased as well. As the activity data for light heating oil is based on the sold amount, it fluctuates due to fuel prices and changing storage amounts.

Sulfur Oxides & Nitrogen Oxides - SOx & NOx

SO2 emissions decrease due to the fuel switch from coal (especially lignite with a high emission factor) to natural gas with a lower emission factor.
In contrast to SO2 emissions NOX emission trend is less influenced by fuel characteristics but more by combustion conditions. Therefore NOX emission values shows lower reduction. During the last years the use of firewood gain influence.

Non-Methane Volatile Organic Compounds & Carbon Monoxide - NMVOC & CO

Main driver of the NMVOC emission trend is the decreasing lignite consumption. In the residential sector the emission trend is also affected by the increasing use of firewood with high emission factors which levels off the emission reduction.
The explanation for decreasing carbon monoxide emissions is similar to the trend discussion for SO2 and NMVOC. Since 1990 the fuel use changed from solid fuels, which causes high CO-emissions, to gaseous fuels, which produce less CO emissions.

Particulate Matter - PM2.5 & PM10 & TSP

The emission trend for PM2.5, PM10, and TSP are also influenced severely by decreasing coal consumption in small combustion plants, particularly in the period from 1990 to 1994. Since 1995 the emission trend didn't change hardly. Increasing emissions in the last years are caused by the rising wood combustion in residential fire places.

Persistent Organic Pollutants

The main driver of the POPs emission trend are coal and fuelwood. PCDD/F emissions from coal fired furnaces are declining but the effect is retarded by increasing wood consumption. The same influencing variables apply accordingly to the PAH emission trends. The emission trend of HCB shows a high dominance of emissions from wood-burning. Data source for HCB emission factors is the EMEP/Corinair inventory guidebook 2006. Insofar, emission factors are constant from 1990 to 2010. Furthermore, the difference between the EFs for coal and fuelwood is very big. Therefore, the emission trend depends solely on the development of fuelwood consumption. Regarding HCB emissions the inventory is incomplete. This is one of the reasons for the importance of emissions from small combustion plants.

Recalculations

Recalculations were necessary for the latest reference year (2009) due to the availability of the National Energy Balance. Germany has a federal structure which causes a time lack of the National Energy Balance. Therefore recalculations are always necessary.

Planned improvements

It´s planned to improve the time series consistency of all emission factors.